New Predictors for the Weaning from Mechanical Ventilation

Abstract

New indicators, Oxygen Cost of Breathing (ΔV_O2), Work of Breathing (WOBp), intrapreural Pressure Time Product (PTP) and P_0.1 were clinically examined to determine which of these indicators is the most specific and sensitive for predicting the outcome of weaning from mechanical ventilation. Twenty-three weanings were attempted and divided into a successful weaning group (Group-S) and a failed weaning group (Group-F). There were significant differences in Minute Volume, ΔV_O2, ΔV_CO2, WOBp, P_0.1, PTP, Lung Compliance and Intrinsic PEEP between the groups. ΔV_O2 and P_0.1 in particular, were statsitically significantly different in the two groups (ΔV_O2: 14.4±11.7 in Group-F VS. -7.7±9.6% in Group-S P<0.005, P_0.1: 4.9±1.6 in Group-F VS. 2.5±1.3cmH₂O in Group-S P<0.01) and 5% in ΔV_O2 and 3.5cmH₂O in P_0.1 are the Cutt-Off values for prediction of the success or failure of weaning trials. WOBp greater than 9 Joule min^-1 and PTP above 200cmH₂O sec min^-1 suggested difficulty in weaning from the ventilator. ΔV_O2 and P_0.1 are considered to be the most sensitive indicators, because in the group-F these indicators exhibited significant increases in the early stage of weaning from the ventilator.